Some trucks have containers that roll off and on the truck bed. Typical roll-off trucks have a pair of rails that extend along the truck bed and pivot upwardly creating a ramp on which a container rolls on or off, aided by a cable hoist system or a hydraulic hook for loading or unloading the container.
Roll-off containers must have a secondary locking system that is engaged during transport. Typically, containers are secured with straps, chains, or a powered automatic locking system. These systems require an operator to perform some activity before loading or unloading a container. It is possible for an operator to forget to attach the straps or chains or to activate the power lock before driving off. Also, if the operator were to forget to remove the straps or chains or to deactivate the power lock before rolling the container off, damage to the container, hoist, truck, or locking device could occur.